Dental Implant Ratchet Wrench? 7mm. Engine Latch Driver/4mm Square Adapter. Implant torque wrench with adapter. Medical Grade Stainless Steel. Hole Diameter: 7mm (0.2756 inch). Contra angle driver to hand driver. Hole size: 4mm square. The sale of this item may be subject to regulation by the U. Food and Drug Administration and state and local regulatory agencies. City State: Zhengzhou, Henan China.